The main problem with ion cannons is that they bloom something fierce.
True, but what are the alternatives? Laser Cannons are either going to huge mirrors with massive heat waste ontop of a gigantic power bill, relativistic weaponry may not fit on a ship worth being a ship/wear down too much in the case of railguns, missiles may be too slow, easy to shoot down, and massive to lug around, regular bullets may work early on in near earth space with 'slow' ships but not much else elsewhere with 'fast' ships over a hundred thousand KM, and what am I missing? Drones just take the problems onto themselves like a yoke. MASERs seem like a dead end.
One needs a weapon for ships that is not massive, not too 'hot', not too powerhungry by itself, and reaches the enemy quickly and with destructive force.
Admittedly, even particle accelerators may not impart much force on a target after their flight...what does that leave? Hypersonic kinetics?
UREB's (ultra-relativistic electron beams) can also be an excellent space-to-space beam weapon. Electron beams tend to suffer a lot from electrostatic blooming, but this can be mitigated by yeeting them at extremely relativistic (like 0.999999...c) velocities, slowing down their blooming through relativistic effects. This can in theory be done with any type of particle beam, but is the easiest to do with electrons as they have the highest possible charge to mass ratio.